1. Field of the Invention
The present invention relates to a web winding apparatus, and more particularly to a web winding apparatus adapted for use in association with an automatic developing unit so as to wind a developed photosensitive sheet automatically.
2. Description of the Prior Art
To explain the background of the present invention reference will be made to FIG. 10:
An exposed photosensitive sheet 4 is subjected to a series of developing treatments while passing through a developer tank 6, a fixing tank 8, a cleansing tank 10 and a drying section 12, and is then finally wound around a winder 14. Hereinafter, the photosensitive sheet to be wound will be referred to merely as a "sheet".
As depicted in FIGS. 11 and 12, winder 14 includes a pair of side plates 16, two driving rollers 18, 20 carried between the side plates 16, and a reel 24 which is made up of a shaft 21 and flanges 22 provided at opposite ends of the shaft 21. A stop 25 limits movement of the flanges 22 along the driving rollers 18 and 20. The rollers 18 and 20 contact the peripheries of the flanges 22 to impart frictional drive thereto.
The reel 24 rotates in accordance with the rotation of either of the rollers 18, 20 or both by a motor 26. The rotating speed of the reel 24 depends upon the feeding speed of the sheet 4 in the developing unit. Consequently there is unavoidably some degree of slip occurring between the flanges 22 and the rollers 18, 20.
In the developing units it often happens that the feeding sheet tends to fluctuate in a zigzag manner. When the sheet is fed in this manner and placed on the reel, the roll of the sheet has different thicknesses at opposite ends of the winding shaft. In general, when a sheet is wound around the shaft it is essential that the advancing direction of the sheet should be perpendicular to the axis of the winding shaft. The fluctuation of the feeding sheet leads to detrimental creases and/or folds when it is wound on the shaft.